Hierarchical layered double hydroxide epitaxially grown on vermiculite for Cr(VI) removal

• Assembled MgAl–LDH on the surface of VMT is achieved via in situ growing technique.
• The growth mechanism was attributed to lattice match between the VMT and MgAl–LDH.
• Shows high adsorption capacity and excellent regeneration property for Cr(VI).
• The transfer channel and mass diffusion of MgAl–LDH/VMT are highly enhanced.

Hierarchical MgAl–layered double hydroxide (MgAl–LDH) was fabricated both on the external and interlayer surfaces of natural mineral vermiculite (VMT) via in situ epitaxial growing technique. The fabrication of the MgAl–LDH/VMT was achieved by lattice match of VMT with MgAl–LDH, which indicates MgAl–LDH can adopt a tilted orientation to the VMT surface. Compared with traditional MgAl–LDH, the hierarchically structured MgAl–LDH/VMT exhibits higher sorption-regeneration performance for Cr(VI), since the specific surface area and transfer channel are significantly enhanced due to its porous 3D framework. The 3D hierarchical MgAl–LDH/VMT can be potentially used as a structured adsorbent in waste water treatment.